1. Field of the Invention
The present invention relates to a process for preparing non-amalgamated zinc alloy powder for alkali dry cells and, more particularly, to a process for preparing non-amalgamated zinc alloy powder for alkali dry cells capable of being employed as an active material for an anode of the alkali dry cell.
2. Description of Related Art
Conventional zinc alkali dry cells have the problem in common that the zinc anode is corroded by an electrolytic solution during storage. In order to solve the problem as industrical means, hydrogen overvoltage is elevated by using amalgamated zinc powders containing approximately 5% to 10% by weight of mercury, thereby suppressing corrosion to such an extent as causing no practical problem.
Recently, however, as social demand has been increased, various research has been made in order to reduce mercury in the cell and combat with pollution. Nowadays, for instance, as disclosed in Japanese Patent Publication (kokoku) No. 42,114/1989, there has been employed zinc alloy powder containing approximately 0.6% by weight of mercury, which is prepared by amalgamating zinc alloy containing lead or aluminum with an indium-mercury alloy.
It is to be noted that, even if mercury has been reduced to the amount as low as approximately 0.6% by weight, mercury is still contained and the problem with environmental pollution cannot be said to be solved. Further, from the resource point of view, it is desired to reproduce zinc and so on from used dry cells, the mercury contained in the cells, whatever the amount of mercury is, causes the problem in reproduction steps.